Otto Warmbier (L) is seen heading to his March 16, 2016, trial in Pyongyang, North Korea. The U.S. citizen was sentenced to 15 years of hard labor for stealing a propaganda poster. He was released on Tuesday. Photo courtesy of Korea Central News Agency/EPA

June 13 (UPI) -- North Korean officials released a U.S. citizen held in prison for 17 months, Secretary of State Rex Tillerson announced Tuesday.

Otto Warmbier, 23, a Cincinnati resident and University of Virginia student, is "en route to the United States," Tillerson's statement said. He added the State Department secured Warmbier's release "at the direction of the president."

His family said he has been in a coma for more than a year, adding that he became ill after his March 2016 trial in Pyongyang. It was his last public appearance.

Warmbier visited North Korea as part of a group tour in 2016, and was about to take a flight home when he was arrested. He was sentenced to 15 years of hard labor for attempting to steal a propaganda poster from a hotel, he said, to give to a friend in the United States in exchange for a used car. While in detention he called the action "the worst mistake of my life," although it is unclear if his comment was coerced or sincere.

Three U.S. citizens, all Korean Americans, remain in North Korean jails.

Freeing Warmbier could signal a conciliatory tone by Pyongyang toward Washington amid intensifying pressure from the United States over North Korea's nuclear and missile programs, the Korea Times reported Tuesday.